This invention relates to broadcast automation systems, and more particularly to a method for rapid start-up for these systems.
Present-day broadcast automation systems generally work on the concept of a xe2x80x9cplaylistxe2x80x9d, also known as a schedule of events. These events are commands to video devices to play pieces of audio/visual material, insert special effects, acquire video from a particular input device, direct video to particular output devices, and other activities related to audio/video broadcasting.
Broadcast automation systems operate by loading the events of an entire playlist sequentially, all at once. While the playlist is loading, the system is unavailable for other processing while this initial playlist is loading. While the system can subsequently accept changes, called xe2x80x9ceditsxe2x80x9d to the playlist, the processing of edits is limited. A large number of edits in rapid succession can make the systems unavailable while the edits are being processed. Moreover, edits to events that will not occur until far in the future, for instance, appending additional material to the playlist, can indefinitely delay edits to events that will occur sooner. This can result in lost edits or erroneous execution of the playlist.
In an exemplary embodiment of the invention, a software component called a xe2x80x9cthrottlerxe2x80x9d allows playlist loads and edits to be interleaved with other actions such as sending commands to devices and interacting with an operator. External components that load and edit the playlist send editing commands. Each command represents either an insertion or a deletion of an event. Modification to an existing event is expressed as a deletion of the existing event, followed by an insertion of the modified event. Every event has a unique xe2x80x9cevent identifierxe2x80x9d which points to a rapidly accessible data structure of command pairs of insertion and deletion edits for that event, ordered by urgency.
The interleaving of commands has a number of advantages over the state of the art systems. First, it allows the video devices to receive an incomplete schedule immediately, and begin executing it even while later events in the playlist are still being processed. By delivering the events that are close to air, it allows the system to go on air sooner than if the entire playlist had to be loaded before any video actions could begin. Second, it allows the video devices to report on the status of events in the playlist even before the download of the playlist is complete, allowing the system to capture a timely record of the video that actually played for purposes such as accounting and fault analysis. Third, it allows the operator interface to remain xe2x80x9clivexe2x80x9d during the initial download of commands to the video equipment. The operator can determine the status of equipment, view the complete or incomplete playlist, interact with the devices, and request edits to the playlist, even while the initial download is proceeding.